CM871 fuel mileage

[superbudy208]

So like I said the fuel mileage get worse i suspect because it lugs the motor down around 1250 to 1300 rpms, so sounds like gears are needed, the truck does like to run 70 to 72 mph and the engine runs around 1400 to 1500 rpms and seems happy, today driving the truck i can not get the engine to rev past 1700 in 8th or 9th gear and will slow down from 1700 rpms down to 1500 before it goes again kinda strange!

So the original data plate is missing because it appears the valve cover has been changed, I still need to get the paper work and read over every line by line! ESN for the truck is 79281998, I'm not sure how to post a pic in here yet this is the first forum I've been on. When i tried talking to the dealer they made it seem like it was normal but, as I've been driving and fixing things on the truck I can also tell the fixed the problem but not the issue that caused the problem, like the truck got 2 transmission's one from pete and one from kenworth, but they did not replace the shifter and found it was not shifting out of reverse all the way and that was a bad trip at 3 mpg's

Also don't have insite yet but the adapter is in the mail and should be here by Friday

So I do know it had new Cummins cylinder head installed, but not sure on the numbers but I will get them in the next tomorrow, just got home and the wife has surgery and will be down for a few days.

No I don't think another over head was done at 50k when I talked to the owner about it he said it don't need one till 500k but the weather was horrible so had the dealer do it, but no difference was felt.

No I have not pressure tested the system but I can do that, and there's no fuel leaks it did have fuel line's that were coming apart, and all the fuel lines have been replaced, from front to rear going both directions with all new fittings and I better get some wedges to check the timing.

Also suspect maybe a chassis problem of the rear axles there are several shims on one side and I do know the front shackles need to be replaced and has a slight clunk at times ,and the right front axle inner tire has a funny wear pattern in it.